Tube severing device

ABSTRACT

A cylindrical housing is dimensioned for insertion in a heat exchanger tube. The housing is formed with a bore extending therethrough and located eccentrically relative to the axis of the housing. A shaft is journaled in the bore and is provided at its inner end with a tube penetrating rib arranged eccentrically with the axis of the shaft. The eccentricity of the shaft penetrating rib relative to the axis of the shaft is comparable to the eccentricity of the housing relative to the axis of the shaft, whereby the penetrating shaft rib may be positioned in registration with the inner end of the housing to permit the same to be inserted in the tube. Driving means is operable to effect rotation of the shaft moving the penetrating rib thereon into engagement with the inner surface of the tube. This rotation on the shaft extends through a part of a revolution and thereupon, the driving means effects rotation of the shaft and the housing in unison effecting complete severance of the tube.

iinited States Patent 1191 Miller Inventor:

[52 us. c1. 82/82, 30/104, 82/4 R 51 1111. C1 1323b 5/14 [58] Field of Search 82/82, 4 R; 83/54, 184,

[56] References Cited UNITED STATES PATENTS 2,028,578 1/193'6 Vl/iedeke 30/104 2,840,902 1/1958 lannettL; 30/104 I FOREIGN PATENTS OR APPLICATIONS 23,584 7/1913 Norway 30/104 798,779 3/1936 France 30/103 481,933 3/1952 Canada 82/82 Primary Examiner-Andrew R. Juhasz Assistant Examiner-W. Briggs Attorney, Agent, or Firm-J. Raymond Curtin;

' Thomas J. Wall 1 51 May 14, 1974 ABSTRACT A cylindrical housing is dimensioned for insertion in a heat exchanger tube. The housing is formed with a bore extending therethrough and located eccentrically relative to the axis of the housing. A shaft is journaled in the bore and is provided at its inner end with a tube penetrating rib arranged eccentrically with the axis of the shaft. The eccentricity of the shaft penetrating rib relative to the axis of the shaft is comparable to the eccentricity of the housing relative to the axis of the shaft, whereby the penetrating shaft rib may be positioned in registration with the inner end of the housing to permit the same to be inserted in the tube. Driving means is operable to effect rotation of the shaft moving the penetrating rib thereon into engagement with the inner surface of the tube. This rotation on the shaft extends through a part of a revolution and thereupon, the driving means effects rotation of the shaft and the housing in unison effecting complete severance of the tube.

11 Claims, 6 Drawing Figures W TUBE SEVERING DEVICE BACKGROUND OF THE INVENTION 7 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the housing is of elongated It is well known that upon occasion, it is necessary to 5 cylindrical form with the major Portion of the housing remove defective heat exchanging tubes from a heat exchanger and replace them with new tubes. In the process of extracting the defective tubes, it is conventional practice to sever the tube a short distance inwardly from one of the tube sheets, the tube thereafter being withdrawn through the tube sheet at the opposite end of the heat exchanger shell, and subsequently the severed stub portion extracted from the first tube sheet.

Devices have been developed for severing the tube inwardly from a tube sheet. One such device includes a rotary cutter mounted on the inner end of the shaft extending into the tube. The shaft is rotated by a driver located exteriorly of the tube and tube sheet, and manipulated manually to move the rotating cutter in an orbital path for engagement with the tube. While such devices do effect a severance of the tube, they are expensive to fabricate, especially as to the rotating cutter, and the latter has to be frequently resharpened. In another type of tool, a shaft is dimensioned for a close free running fit with the interior of the tube. A thin blade type cutter is'carried at the inner end of the shaft and is moved or expanded outwardly in engagement with the tube. In that type, cutter breakage is high.

This invention has as an object an internal tube severing device involving few parts, manufactured at low cost, the device operating for the severance of a very large number of tubes without maintenance and requiring no resharpening of other reconditioning.

SUMMARY OF THE INVENTION A shaft is journaled in a bore located eccentrically in a housing dimensioned for insertion in the tube. The inner end of the shaft is provided with a tube engaging rib which is located eccentrically of the axis of the shaft, the eccentricity of the penetrating rib being equal to the eccentricity of the bore in the housing, whereby the penetrating rib may be arranged in registration with the housing, extending only a short distance beyond the periphery thereof, so that the assembly can be inserted in the tube. The shaft has means for connection to a driver, such as an impact wrench, and upon rotation through part of a revolution, the penetrating rib is moved outwardly from the periphery of the housing for penetration of the side wall of the tube, the housing with the shaft rib extending radially from the periphery thereof, is rotated in unison with the shaft so that the penetrating rib, in completing the revolution, effects severance of the tube.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a lengthwise sectional view of a tube severing device embodying my invention;

FIG. 2 is a view taken on line 2-2, FIG. 1;

FIG. 3 is a view similar to the left end portion of the structure shown in FIG. 1 with the shaft rotated 180 relative to the housing;

FIG. 4 is a view taken on line 4--4, FIG. 1; FIG. 5 is a view taken on line 55, FIG. 3; and FIG. 6 is a view taken on line 66, FIG. 1.

inserted in the tube 11 expanded in the tube sheet 12. The housing 10 is formed with a circular bore in which a shaft 13 is journaled. The shaft 13 has an outer end portion 15 extending outwardly from the outer end of the housing 10. The inner end of the shaft is provided with a tube penetrating rib 17. The rib 17 is of arcuate form, as shown in FIGS. 2 and 5, extending through an arc of approximately The penetrating rib 17 is located eccentric to the axis of the shaft 13, the eccentricity of the rib 17 being comparable to the eccentricity of the housing relative to the axis of the shaft 13, whereby the penetrating rib 17 may be brought into registration with the inner end of the housing, the rib extending from the periphery thereof a distance equal to at least the major portion of the thickness of the tube side wall. The parts are shown in this position in FIGS. 1 and 2.

Driving means for the device is provided and is shown in the form of a driver 20 which may have a socket 21 for connection to a power operated device such as an impact wrench. The driver 20 is fixed to the shaft as by a set screw 23, FIG. 1. A driven member 25 is fixed to the outer end of the housing as by set screw 27. A thrust bearing 28 is disposed between the confronting surfaces of the driver 20 and the driven member 25. The driven member 25 is formed on its end surface confronting the driver 20 with a semi-circular groove 30. A pin 31 is fixed in the driver 20 and has an end portion extending into the groove 30. With the parts in initial position as shown in FIG. 1, the end portion of the pin 31 is located in the lower end of the groove 30 as shown in FIG. 6. When power driven, the driver 20 is rotated to move the pin 31 in a clockwise direction, FIG. 6. During the initial rotation of the member 20, the pin 31 moves along the arcuate slot 30. When it reaches the end of the slot, clockwise rotation is then also imparted to the driven member 25 and the housing 10.

During the initial rotation of ,the shaft 13, the penetrating rib 17 carried thereby is moved through a part of a rotation which, in the embodiment illustrated, is through an arc of subsstantially FIG. 5 illustrates the rib 17 having advanced through such a movement.

The dotted line 38, FIG. 2, indicates the circular path in which the rib 17 moves. It will be seen that the rib 17 passes through the side wall of the tube 11 at 37, the maximum offset of the rib 17 relative to the housing being at 38. Upon rotation of the housing 10 and shaft 13 in unison, the offset rib 17 effects further severance of the tube side wall. Upon rotation of the shaft 13 from the position shown in FIG. 1, and in full lines, FIG. 2, moving the rib 17 into engagement with the tube, the housing 10 is moved upwardly, FIGS. 3 and 5, against the inner surface of the tube. Preferably, the inner end of the housing 10 is also provided with an arcuate tube penetrating rib 45, see FIGS. 1, 4 and 5. If the inner end of the housing is provided with the rib 45, it is forced into the tube during the initial rotation of the shaft 13, see FIG. 5. In that case, the tube is also penetrated between the areas indicated at 47, 48, FIG. 2 and as shown in FIG. 5. Accordingly, upon the initial rotation of the shaft 13, the major portion of the tube is severed. As the housing and shaft are rotated in unison during the remainder of the revolution, the housing rib 45 will sever the tube between the areas 37 and 48, FIG. 2, and the shaft rib 17 will sever the tube between the areas 40 and 47. Preferably, the inner end of the shaft is formed with a cylindrical portion 50 having some axial length. Upon initial rotation of the shaft through the 180 are, it will be apparent that the housing and the end portion 50 of the shaft, because of the eccentricity of the arrangement, create a very substantial outward force in diametrically opposed areas of the tube.

The tube is shown in the drawings as an unprocessed tube having smooth inner and outer surfaces. It is conventional practice to form tubes for a heat exchanger with closely spaced circumferentially extending ribs, or with a helical rib, on the outer surface of the tube to increase the heat transfer therethrough. The cold working of the tube in the formation of the rib structure results in the tube becoming work-hardened and relatively brittle. When the tool of my invention is used in such work-hardened tubes, the initial rotation of the shaft 13 through the 180 arc will result in the tube being broken between the areas 37, 48 and 40,47. When used on such work-hardened tubes, the tube is severed in a matter of 2 or 3 seconds. Even if not completely severed at the end of the initial rotation of the shaft 13, the major portion of the work-hardened tube, pulled through the tube sheet at the opposite end of the heat exchanger, will break away from the portion in which the tool is positioned.

While I have described a preferred embodiment of my invention, it should be understood that the invention is not limited thereto, but may be otherwise embodied within the scope of the following claims.

I claim:

1. An internal tube severing device comprising an elongated housing member circular in cross section and having a diameter slightly less than the internal diameter of the tube, said housing member being formed with being disposed eccentrically to the axis of said shaft and abutting the inner end of said housing, the eccentricity of said rib portion, relative to the axis of said shaft, being comparable to the eccentricity of the housing relative to the axis of said shaft, whereby said rib portion may be positioned in registration with said housing member for insertion of the inner end portion of same into the tube, the outer end portion of said housing extending outwardly from the end of said tube and the outer end portion of said shaft extending outwardly from the outer end portion of said housing, and driving means mounted on the outer ends of said housing and shaft and being operably connected to both the housing and the shaft to automatically rotate only said shaft initially through part ofa revolution and to subsequently effect rotation of said housing and shaft in unison through the remainder of the revolution.

2. A tube severing device as set forth in claim 1 wherein said driving means effects initial rotation of said shaft through an arc of substantially 180.

3. A tube severing device as set forth in claim 1 wherein the inner end of said housing is provided on the periphery thereof in the area of maximum eccentricity relative to the axis of said shaft with a tube penetrating rib.

4. A tube severing device as set forth in claim 1 wherein said penetrating rib portion of said shaft is of arcuate form extending through an arc of substantially 5. An internal tube severing device as set forth in claim 3 wherein said tube penetrating rib on said housing is of arcuate form extending through an arc of substantially 90.

6. An internal tube severing device as set forth in claim 1 wherein said driving means includes a driven member fixed to the outer end of said housing and a driving member fixed to the outer end of said shaft and motion transmitting means connecting said members upon rotation of said driving member through an arc of l80.

7. A tube severing device as set forth in claim 1 wherein the inner end portion of said shaft is of cylindrical formation arranged eccentric to the axis of said shaft and said penetrating rib is affixed to the periphery of said cylindrical portion in the area of maximum eccentricity thereof.

8. An internal tube severing apparatus including a pair of cutting ribs, an elongated housing capable of being inserted into the tube for eccentrically supporting one of said cutting ribs substantially perpendicular to the axial centerline of said housing, said ribs extending beyond the outer periphery of said housing a distance at least equal to the wall thickness of said tube,

an elongated shaft eccentrically mounted within said housing and passing beyond the tube insertable end thereof, said shaft eccentrically supporting said second cutting rib in parallel alignment with said first cutting rib, the eccentricity of said second rib relative to the axis of said shaft being comparable to the eccentricity of the housing relative to the axis of said shaft whereby said second rib is registrable with the outer periphery of said first rib for insertion therewith into said tube,

means operable to initially rotate only said shaft through a part of a single revolution and to subsequently effect rotation of said housing and said shaft in unison through the remainder of said revolution whereby both cutting discs are passed through the wall of said tube.

9. The apparatus of claim 8 wherein said shaft is initially rotated through of one revolution prior to the rotation of said housing whereby the cutting ribs act substantially in opposition to each other as they penetrate the tube wall.

10. The apparatus of claim 9 wherein the terminal end of said shaft passing beyond said housing is provided with a bearing surface adapted to contact the inner wall of said tube for further supporting the cutting ribs as they are rotated therein.

11. The apparatus of claim 8 wherein said cutting ribs are disc shaped and are supported in face-to-face sliding parallel abutment with each other. 

1. An internal tube severing device comprising an elongated housing member circular in cross section and having a diameter slightly less than the internal diameter of the tube, said housing member being formed with a through axial bore located eccentrically relative to the axis of the housing, a shaft journaled in said bore and provided at its inner end with a radially outwardly extending tube penetrating rib portion, said rib portion being disposed eccentrically to the axis of said shaft and abutting the inner end of said housing, the eccentricity of said rib portion, relative to the axis of said shaft, being comparable to the eccentricity of the housing relative to the axis of said shaft, whereby said rib portion may be positioned in registration with said housing member for insertion of the inner end portion of same into the tube, the outer end portion of said housing extending outwardly from the end of said tube and the outer end portion of said shaft extending outwardly from the outer end portion of said housing, and driving means mounted on the outer ends of said housing and shaft and being operably connected to both the housing and the shaft to automatically rotate only said shaft initially through part of a revolution and to subsequently effect rotation of said housing and shaft in unison through the remainder of the revolution.
 2. A tube severing device as set forth in claim 1 wherein said driving means effects initial rotation of said shaft through an arc of substantially 180*.
 3. A tube severing device as set forth in claim 1 wherein the inner end of said housing is provided on the periphery thereof in the area of maximum eccentricity relative to the axis of said shaft with a tube penetrating rib.
 4. A tube severing device as set forth in claim 1 wherein said penetrating rib portion of said shaft is of arcuate form extending through an arc of substantially 90* .
 5. An internal tube severing device as set forth in claim 3 wherein saId tube penetrating rib on said housing is of arcuate form extending through an arc of substantially 90*.
 6. An internal tube severing device as set forth in claim 1 wherein said driving means includes a driven member fixed to the outer end of said housing and a driving member fixed to the outer end of said shaft and motion transmitting means connecting said members upon rotation of said driving member through an arc of 180*.
 7. A tube severing device as set forth in claim 1 wherein the inner end portion of said shaft is of cylindrical formation arranged eccentric to the axis of said shaft and said penetrating rib is affixed to the periphery of said cylindrical portion in the area of maximum eccentricity thereof.
 8. An internal tube severing apparatus including a pair of cutting ribs, an elongated housing capable of being inserted into the tube for eccentrically supporting one of said cutting ribs substantially perpendicular to the axial centerline of said housing, said ribs extending beyond the outer periphery of said housing a distance at least equal to the wall thickness of said tube, an elongated shaft eccentrically mounted within said housing and passing beyond the tube insertable end thereof, said shaft eccentrically supporting said second cutting rib in parallel alignment with said first cutting rib, the eccentricity of said second rib relative to the axis of said shaft being comparable to the eccentricity of the housing relative to the axis of said shaft whereby said second rib is registrable with the outer periphery of said first rib for insertion therewith into said tube, means operable to initially rotate only said shaft through a part of a single revolution and to subsequently effect rotation of said housing and said shaft in unison through the remainder of said revolution whereby both cutting discs are passed through the wall of said tube.
 9. The apparatus of claim 8 wherein said shaft is initially rotated through 180* of one revolution prior to the rotation of said housing whereby the cutting ribs act substantially in opposition to each other as they penetrate the tube wall.
 10. The apparatus of claim 9 wherein the terminal end of said shaft passing beyond said housing is provided with a bearing surface adapted to contact the inner wall of said tube for further supporting the cutting ribs as they are rotated therein.
 11. The apparatus of claim 8 wherein said cutting ribs are disc shaped and are supported in face-to-face sliding parallel abutment with each other. 